Tactical Talk (Update) Britain and the European Union made a significant step forward Friday in Brexit talks, officials said, after a flurry of overnight diplomacy by phone bridged differences over the Irish border. “I believe that we have now made the breakthrough that we needed,” European Commission President Jean-Claude Juncker said at a joint news conference with British Prime Minister Theresa May. But the agreement doesn’t give details of how the thorny border issue will be solved, noting that much depends on the outcome of trade talks between Britain and the EU. Its crucial passages promise that whatever happens, the UK will maintain “full regulatory alignment” with the bloc on issues affecting Ireland, the AP reports.

Exactly what “full alignment” means will be fought over by politicians and negotiators in the months to come. Juncker said that he would recommend to European Union leaders that “sufficient progress has been achieved” on the terms of the divorce to starting talking about issues like future relations and trade. EU leaders meet in Brussels on Dec. 14 and are likely to endorse the assessment that enough progress has been made on the terms of Britain’s financial settlement, the status of Irish borders, and the rights of citizens hit by Brexit. Britain leaves the EU on March 29, 2019, but negotiations must be wrapped up within a year to leave time for parliaments to endorse any deal.